(a) The General Counsel may impose conditions or restrictions on the testimony of OPM employees including, for example, limiting the areas of testimony or requiring the requester and other parties to the legal proceeding to agree that the transcript of the testimony will be kept under seal or will only be used or made available in the particular legal proceeding for which testimony was requested. The General Counsel may also require a copy of the transcript of testimony at the requester's expense.

(b) OPM may offer the employee's written declaration in lieu of testimony.

(c) If authorized to testify pursuant to this part, an employee may testify as to facts within his or her personal knowledge, but, unless specifically authorized to do so by the General Counsel, the employee shall not:

(1) Disclose confidential or privileged information;

(2) Testify as to facts when the General Counsel determines such testimony would not be in the best interest of OPM or the United States; or

(3) For a current OPM employee, testify as an expert or opinion witness with regard to any matter arising out of the employee's official duties or the functions of OPM unless testimony is being given on behalf of the United States.